Within the food industry, beverages and other products are often packed in paper or paperboard based packages. Packages intended for liquid food are often produced from a packaging laminate comprising a core layer of paper or paperboard and an outer, liquid-tight layer of thermoplastic material on at least that side of the core layer which will form the inside of the packages.
One kind of frequently occurring packages are the so-called carton bottles. In substance, these are composed of a lower part in the form of a sleeve of packaging laminate like the one described above, and an upper part in the form of a plastic top having a neck which is provided with an opening/closing means, such as a screw cap. The carton bottles are often produced in that sheets, so-called blanks, of packaging laminate are formed into tubes which are closed by sealing of two opposing edges of each sheet in an overlapping condition. Then, according to a first alternative, each tube is closed at one end by a top of thermoplastic material being directly injection-molded onto the tube at that end. The injection-molded top has a neck sealed by a membrane. In connection with a first time opening of the package, this membrane should be torn off along a tear notch, which is also produced in the injection-molding operation, to enable consumption of the product in the package. After injection-molding, the package is filled, sealed at the open end of the tube for achieving a sleeve and closing the package, and formed into the desired shape. Finally, the neck of the top is provided with a screw cap to enable opening and closing of the package when the membrane has been removed. Packages of this kind are commercialized by the applicant under the name Tetra Top (registered trade mark).
According to a second alternative, instead of injection-molding a top directly onto the tube, the tube is slipped over a respective premade plastic top and arranged in such a way that a major part of the top protrudes from the tube. The premade top has a neck closed by a screw cap. After sealing of the top and the tube along a contact surface between them, the package is filled, sealed at the open end of the tube for achieving a sleeve and closing the package, and finally formed into the desired shape. As opposed to the package described in the paragraph above, this package has a one-step opening since no membrane needs to be removed to open the package. Packages of this kind are commercialized by the applicant under the name Tetra Aptiva (registered trade mark).
Injection-molding of a top directly onto a tube in production of a package is, in many situations, desirable. On the other hand, a one-step opening of a package may also often be preferable. Reasons for this are, among others, that the first time opening of a two-step opening package often will result in a loose part, for example in the form of a membrane, which loose part could increase the risk of littering or of children choking when being in contact with the package. In U.S. Pat. No. 4,518,554, a method and an apparatus for molding a container enabling a combination of these two features are disclosed. In accordance with this document, a cap is arranged with its open end facing outwardly in a female die. A male die, which is insertable into the female die and into the cap when the cap is arranged therein, is also provided. A top end portion of a preformed container body is partly inserted into the cavity formed between the female die with the cap arranged therein and the male die. Then, a synthetic resin is injected into the cavity to form the neck portion on the container body.
To give a consumer the possibility of investigating whether a package has been opened earlier, different types of safety means, so-called tamper proofs, exist. These are broken by the consumer in connection with a first time opening of the package.
The first package described above, whose top is injection-molded directly onto the tube, has a built-in tamper proof in the form of the membrane. To be able to open this package (in the proper way) for the first time, the membrane needs to be removed. Thus, if the membrane is removed, the consumer knows that the package has been opened earlier.
The second package described above, whose top is pre-made before assembly with the tube, can be provided with a well-known taper proof in the form of a ring which, through breakable, thin connections spaced evenly along the ring, is attached to the bottom end of the screw cap. The ring is permanently connected to the neck of the top which means that the connections between the ring and the cap must be broken to enable removal of the cap from the package in connection with opening of the same. Thus, if the ring is disconnected from the cap, the consumer knows that the package has been opened earlier. The ring is locked to the neck by an annular flange arranged at a predetermined distance from the pouring opening of the package. The flange permits rotation of the ring but hinders movement of the ring in an upward longitudinal direction of the package. When the screw cap is turned for opening of the package, the threading forces the cap in the upward longitudinal direction. Since movement of the ring is obstructed in this direction, the thin connections between the ring and the cap are broken, one by one, by the cap turning. The ring is formed integrally with the screw cap and applied onto the top in connection with the capping operation.
The third package described above, whose neck portion is directly injection-molded into the screw cap and onto the container body, has no built-in tamper proof. Further, a tamper proof as the one described above cannot be used in connection with this package since the resin injected into the cavity between the dies will fill all open spaces, also the open spaces between the ring and the screw cap. Thus, after such an injection, the spaces between the breakable ring-cap connections will be filled with resin. This will prevent the ring from rotating in connection with turning of the cap which means that all the connections between the ring and the cap will have to be broken essentially at the same time to enable opening of the package. Such an operation requires very high strength and the package will be extremely hard, or even impossible, to open. Clearly, this kind of tamper proof is very badly suited for this application. Accordingly, there exists a great need for a working tamper solution for packages of this and similar types.